Mental Unity, Altered States of Consciousness & Dissociation I
LouisTinnin, M.D., is Associate Professorin the Department THE ORIGIN OF CONSCIOUSNESS of Behavioral Medicine and Psychiatry at West Virginia University, Morgantown, West Virginia. ormal consciousness has its origin in the development of the "triune brain" (MacLean, 1973). This brain is a For reprints write to Louis Tinnin, M.D., WVU Department hierarchical organization of three different mentalities, a ofBehavioral Medicine and Psychiatry, ChestnutRidge Hos result of the evolutionary development of the human brain pital, 930 Chestnut Ridge Road, Morgantown, WV 26505. which preserved the ancestral brain components ofreptiles, early mammals, and late mammals. The oldest component, ABSTRACT the reptilian, contributes the brainstem and much of the reticularsystem. Thenextlevel, the paleomammalian, consists This model for understanding altered states of consciousness and of the limbic system and the midbrain and is largely re dissociation is based on the hypothesis that normal consciousness sponsible for emotion. The upper level ofthe triune brain is depends on an illusion ofmentalunitygenerated by certain dynamic the neomammalian, orthe neocortex,which MacLean (1973) brain processes. When these processes are altered and the illusion of believes to be the matrix for intellectual function, including mental unity is lost, the individual experiences an altered state of consciousness. consciousness inwhich normalconsciousness is latent or "dissociated. " Consciousness developed afterthe neomammalian brain Mental organizationsformed during an altered state will, in turn, expanded laterally into large dual cerebral hemispheres become dissociated when the altered state is terminated and mental connected by a bridge offibers, the corpus callosum, which unity returns. In some cases, recurrent altered states may lead to first emergedin the placentalmammals (Levy, 1985).
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